I'm currently working with a customer who's got a service provider edition of Microsoft CRM.
I am developing callouts and will write some more about what the differences are, for now I will leave you with a reference to a blog that actually mentiones something about this.
For one, there is a different version of Microsoft.Crm.Platform.Callout.Base.dll and there is a different way of authenticating when using the webservice. I will write I bit more about it later.
Have a look at this blog for now: Microsoft.Crm.Platform.Callout.Base.dll
CRM and SharePoint Consultant